longbow layout

[bigcountry]

I have built osage bow with a pyamid type of layout.  Bascially 4" handle, 2" fades, to 1.75".  I would then keep that 1.75" profile up 12" on each limb, and then pyamid out to 3/8" tips. 

I have been thinking about a pure pyamid design, basically starting at the fades all the way to the tips.

Is there any disadvanges to this compared to the one I made?

I like performance like we all do.  But also like durability more.

[Pat B]

I use that design all the time and especially with osage. Your limbs will probably come out a bit thicker than with your old design. Pat

[Justin Snyder]

I would never keep Osage at 1.75" to start.  1.5" is plenty if you go direct taper to the tips.  1.25 is good if you want to keep that width for 12".  I think the parallel limb option might be a little more durable.

Of course I am making a broad statement.  Without knowing the bow length and target weight I cannot give you propper advice. Justin

[bigcountry]

I would never keep Osage at 1.75" to start.  1.5" is plenty if you go direct taper to the tips.  1.25 is good if you want to keep that width for 12".  I think the parallel limb option might be a little more durable.

Of course I am making a broad statement.  Without knowing the bow length and target weight I cannot give you propper advice. Justin

Well, when I first built it, I had an osage bow break.  Basically at the fades up the limb.  So, I took a class, and told the guy running it, I wanted a durable bow.  And really wanted a 60lb bow at 29" draw 66" NTN.    So he figured durable is 1.75".   

I think its going to pay off because after tillering (I am still need to fine tiller), its only 40lbs.  So I got some sinew, and thinking of dropping length down to 62" and sinewing.  That should get my wieght up.  And since my draw is 29.5", I figured the extra wide limbs should be able to take the strain even at 62".  Is my thinking wrong?

[Justin Snyder]

No your thinking is not wrong.  I have a couple of Osage bows at 62" and 60# @ 29".  Mine are about 1 1/4" wide for about 12" then taper to the tips.  You will have extra mass that you don't need, but that is not wrong, just different.     Cutting this bow down to 62" is going to give you about 52#. Sinew might add a couple of pounds to that.  I would finish the tiller then if you aren't happy you can cut it down a little and fine tune the tiller again.  At some point you will either decide the bow is good or it will explode or hinge. I hope you decide it is good enough first.   

[bigcountry]

Thanks Justin. 

But does anyone know the performance difference?  Is a pyamid limb bow usually faster due to lack of mass?

[Badger]

       Big, I pulled about 4 osage bows out of the garage the other day just to check a few things, the heaviest bow is 67# and is also the norrowest and has the highest mass weight. The lightest bow is 48# and is physicaly the lightest bow but also the widest and largest physical demensions.
       Idealy when you select a design for your bow you incorporate that into the tiller, A pyramid bow should pretty much have an arc of the circle tiller, where a bow with paralell limbs for a certain distance should have a more elyptical tiller. Lets say you made the first 16" of the limb paralell but when you tillered it you tillered a nice arc of the circle tiller. Your mid limb would be stressed far less than near handle wood, this will give you more vibration in the bow and possibly more set near the handle. Thats one of the reasons I started using mass to dictate my demensions for a bow, just too much variance in wood density. I like and use both designs you mentioned but more based on how much wood I have to work with. A pyramid bow will carry less mass but will not neccessarily be faster.
       If I was going to make a 60#@29.5" pyramid bow I would want it to weigh at least 22 0z, If I was going to make a paralell limb bow of the dsame length and draw I would make it 25 oz with an elyptical tiller. Steve